Summary

Pontine structures are critical for the generation of rapid eye movement sleep but there are only a few reports of the effects of focal pontine lesions on sleep patterns in humans. We report the case of an 81-year-old man admitted for the acute onset of disordered speech and motor deficit in the upper right arm who developed hypersomnia within a week. A 24-hour polysomnographic study revealed a very severe disruption of both circadian rhythm and sleep organisation, and a brain MRI documented an ischaemic lesion of the anterior left paramedian portion of the pons. Our observation suggests that even small, paramedian pontine ischaemic lesions can acutely induce a very severe sleep disorder.